In the art of constructing a building, it is common practice to first construct a foundation of poured concrete set within and projecting up from ground level at the building site and upon which the remainder of the building is to be constructed. In accordance with old and established practices, such a foundation is characterized by a primary exterior portion which extends about the perimeter of the building site and secondary inside portions which are arranged to occur beneath and afford support for certain of the interior wall structures and the like of the building. Further, in accordance with old and established practices, such foundations are established by first digging upwardly opening trenches in the earth to accommodate the foundations; building upwardly opening box-like wooden forms for the foundations; and then pouring and filling the forms with concrete. After the concrete is set, the wooden forms are stripped or removed and the wood or materials thereof are, most frequently, scrapped. As a general rule, such foundations are rectangular in cross-section; are of predetermined minimal vertical and lateral extent and are established with flat, smooth top surfaces which occur on a set predetermined horizontal plane. It is also common practice when constructing the forms for such foundations to exercise care so as to establish a foundation having a smooth, clean and attractive exterior surface (as by using good quality lumber). Less concern is given to the resulting finish of the inside surfaces of such foundations.
In practice, most foundations of the character referred to are provided with and include a plurality of longitudinally spaced upwardly projecting threaded studs. The studs are provided to effectively secure wood boards or timbers to the tops of the foundations, upon which boards the remainder of the building structures are built. Those boards or timbers are called "mud sills" and are generally established of wood which has been treated to resist rot and are so fastened to their related foundations to establish an effective seal therewith. Such mud sills are often considered integral parts of their related foundations structures.
In some buildings, the foundations support fabricated wood floor structures while in other buildings, the interior space or area defined by the foundations are provided with concrete decks or floors which are poured within the confines of the foundation and finished with a smooth top surface which, for example, is even with the top surfaces of the foundations.
In many areas, building codes require the inclusion of metal reinforcing rods in poured concrete foundations of the character here concerned with.
In most instances, the upper portions of foundations of the character here concerned with project upwardly from the surface of the ground six to eight inches and the exterior surfaces thereof are exposed to all outside elements. That is, they are exposed to freezing temperatures, flood waters, and the like.
In the recent past, those who have studied the construction of buildings to determine the major causes of heat loss with the view that steps might be taken to reduce the cost of heating buildings and conserve fuel have discovered that great quantities of heat is transmitted into and out of buildings through and about their foundations. The heat losses at the foundations of buildings, whether it be from within or outside the buildings, is major. As a result of the foregoing, building codes throughout the country are being modified to require that the exposed exterior surfaces of foundations of the character here concerned with be thermally insulated. To date, to the best of my knowledge and belief, no standard and/or approved thermal insulating means for such foundations has been provided by the prior art. Instead, where codes require that foundations be insulated, those codes have been satisfied by simply cementing or otherwise fixing slabs, batting or sheets of some available thermal insulating material to the exterior surfaces of finished foundations, which foundations are established in accordance with old and established practices. Such insulating means are at best "add-ons" which are seldom attractive or structurally sound.